Submitted to: Proceedings of Int'l Association of Plant Tissue Culture and Biotechnology
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2002
Publication Date: 6/16/2002
Citation: Abebe, T., Federico, M.L., Fu, J., Skadsen, R.W., Kaeppler, H.F. 2002. Cloning lemma- and palea-specific promoters in barley. Proceedings of 10th Int'l Association of Plant Tissue Culture and Biotechnology. p. 51-A. Interpretive Summary:
Technical Abstract: Tissue-specific promoters are required for directing expression of economically important genes in target tissues. We are interested in developing lemma- and palea-specific promoters for expressing antifungal genes in barley spikes. The lemma and palea of cereals are sterile bracts that nourish florets and developing kernels. They also protect florets and kernels from mechanical damage and pathogen infection. Because of their unique functions, it is expected that specific genes are preferentially expressed in these organs. These genes are potential sources of tissue-specific promoters. We have constructed cDNA libraries from three developmental stages of the lemma and palea (elongating, gelatinous and early dough kernel stages) of the barley (Hordeum vulgare L.) cultivar Morex using the suppression subtractive hybridization (SSH) method. Using the pooled lemma/palea cDNA as a tester and the flag leaf as a driver, 300 cDNA clones were obtained from each library. Differential screening and northern analysis of selected clones showed that the cDNAs are preferentially expressed in the lemma and palea compared with the leaf. A similarity search to the GenBank databases identified genes with known and unknown functions. A limited number of novel genes were also identified. Among the genes with known functions were those involved in photosynthesis, reactive oxygen species (ROS) scavenging, cell wall biosynthesis, microtubule formation and metabolism. Differential expression of these genes is consistent with the proposed role of the lemma and palea in providing carbohydrates and protection for the florets and developing seeds. Currently we are cloning the promoters of selected lemma- and palea-specific clones by PCR and testing them by particle bombardment.